Please go see your OB soon. My mother had the same problem. She was also overweight and bleeding well after menopause. She had stage 1 uterine cancer had had a hysterectomy done. She is now 3 years cancer free and doing well. The sooner the better you get checked out. Please don't wait!!! and don't let your weight get in the way of seeing you doc trust me they see enough obese people and are use to it.
after menopause, you should not have ANY vaginal bleeding.
you need to have a d&c to evaluate. this is not normal.
Are you absolutely positive it is vaginal fluid? My doc told me when I was pregnant that often pregnant women have urine leaks, because the weight of the stomach area (uterus and baby in their case) presses on the bladder, and out comes urine without them feeling like they are peeing. Pee can be clear and odorless, especially if you drink a lot of water. Given that you are obese, possibly the same thing is happening to you. Later in my pregnancy, my doc suggested I use a timer and train myself to pee once an hour, to be sure there wasn't pressure on my urethra because he said otherwise it might make it ineffective at stopping the urine from leaking out later in life. Maybe that is what is happening to you.
Is it impossible for you to get the weight off? Have you tried Weight Watchers? My husband had extremely good results with it.